DRAINAGE INDICATIONS 



191 



held below the surface until it is removed by the same 

 processes. In both cases, injury is worked to both soil 

 and crop. 



252. Limited flat or depressed areas on hilltops. The 

 soil conditions in this case do not differ from the last 



FIG. 82. To show how a heavy clay soil, surmounting a hill top, as 

 described in paragraph 252, might retain a large amount of water 

 and require draining. 



named except in position. (See Figs. 82 and 83.) A 

 case of this class is mentioned in a previous paragraph. 

 An area of this kind amounting to a half acre was so wet 

 that it could not be spring-plowed in time for a crop. 



^ lORods _ J 



FIG. 83. To show another condition that would result in the over-wet 

 hill top mentioned in paragraph 252. S, any fairly open to open 

 soil. /, an impervious or semi-pervious layer ranging from a few 

 inches to several feet in thickness. It may be underlaid by a very 

 open soil. 



Later in the season a simple system of tile was laid with 

 its outlet 50 yards down the slope, and close to the line 

 fence. After a few years the outlet was connected to a 

 near-by lateral of another tile system. No trouble has 

 been experienced from wet ground on the hill top since 

 the system was installed. 



